The aim of this thesis is to design an air conditioning system of a flat unit in two variants of piping. The piping system of the first floor is installed into the floor in one variant, in the other it is in the ceiling. Data received from measurements within the experiment have been used for the design. The result of the measurement are minor loss coefficient implemented for bending pipes and pressure losses caused by rubbing. These values are used for dimensioning piping variants. Both types of piping are described in the theoretical part and the method of how the experiment had been processed.